Copending application Ser. No. 55,091, filed July 5, 1979, U.S. Pat. No. 4,258,143, relates to modified unsaturated polyesters which are suitable for combining with conventional polymerizable, ethylenically unsaturated monomeric cross-linking agents such as styrene. These polyesters comprise the reaction product of
(a) from about 50 to about 90% by weight (preferably about 50-85%), based on the weight of the reaction product, of an ethylenically unsaturated polyester derived from an .alpha.,.beta.-ethylenically unsaturated dicarboxylic acid with a saturated aliphatic polyol, and PA1 (b) from about 50 to greater than about 10% by weight (preferably about 50-15%), based on the weight of said reaction product, of a modified polyolefin derived by peroxide grafting of an .alpha.,.beta.-ethylenically unsaturated dicarboxylic acid or anhydride and a polyolefin. PA1 (A) at least two aromatic or saturated aliphatic or cycloaliphatic dibasic acid having 4 to 36 carbon atoms, PA1 (B) from about 2 to about 40%, based on the weight of the copolyester, of a carboxylated polyolefin selected from the group consisting of (1) oxidized polyolefins and (2) the reaction product of PA1 (C) at least one saturated aliphatic or cycloaliphatic glycol having from 2 to 12 carbon atoms,
These polyesters preferably contain a polymer or copolymer of an olefin as an additive.
U.S. Pat. No. 3,207,816 discloses that modification of low molecular weight reactive, essentially ethylenically unsaturated polyester resins, prior to cross-linking, by the addition thereto of an alternating copolymer of an .alpha.,.beta.-ethylenically unsaturated dicarboxylic acid or anhydride with a monoolefin having a terminal methylene group, results in linear alkyd resins having higher molecular weights than are readily obtainable by conventional procedures. However, these polymers would be expected to have an I.V. of generally no greater than 0.1. The resulting linear alkyd, due to its improved viscosity, is said to impart many outstanding advantages to polyester resinous compositions prepared therefrom. This patent further discloses, however, that the amount of interpolymer or mixture of interpolymer employed may be from about 0.05% to about 10%, preferably about 0.2% to about 3%, by weight based on the total weight of resin forming components.